Cloud Key

As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Acidic Slime enters the battlefield, destroy target artifact, enchantment, or land.

Farhaven Elf

When Farhaven Elf enters the battlefield, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Peregrin Took

If one or more tokens would be created under your control, those tokens plus an additional Food token are created instead. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Sacrifice three Foods: Draw a card.

Erdwal Illuminator

Flying
Whenever you investigate for the first time each turn, investigate an additional time.

Confirm Suspicions

Counter target spell.
Investigate three times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Counterspell

Song of the Dryads

Enchant permanent
Enchanted permanent is a colorless Forest land.

Island

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Arbor Elf

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Vedalken Heretic

Whenever Vedalken Heretic deals damage to an opponent, you may draw a card.

Forest

Jaheira, Friend of the Forest

Tokens you control have "{T}: Add {G}."
Choose a Background (You can have a Background as a second commander.)

Lonis, Cryptozoologist

Whenever another nontoken creature enters the battlefield under your control, investigate.
{T}, Sacrifice X Clues: Target opponent reveals the top X cards of their library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield under your control. That player puts the rest on the bottom of their library in a random order.

Elvish Visionary

When Elvish Visionary enters the battlefield, draw a card.

Elvish Rejuvenator

When Elvish Rejuvenator enters the battlefield, look at the top five cards of your library. You may put a land card from among them onto the battlefield tapped. Put the rest on the bottom of your library in a random order.

Wall of Runes

Defender (This creature can't attack.)
When Wall of Runes enters the battlefield, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Tireless Provisioner

Landfall — Whenever a land enters the battlefield under your control, create a Food token or a Treasure token. (Food is an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life." Treasure is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Alchemist's Refuge

{T}: Add {C}.
{G}{U}, {T}: You may cast spells this turn as though they had flash.

Universal Surveillance

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Draw X cards.

Mulldrifter

Flying
When Mulldrifter enters the battlefield, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Coiling Oracle

When Coiling Oracle enters the battlefield, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.

Simic Signet

Confront the Unknown

Investigate, then target creature gets +1/+1 until end of turn for each Clue you control. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Soul of the Harvest

Trample
Whenever another nontoken creature enters the battlefield under your control, you may draw a card.

Dream Stalker

When Dream Stalker enters the battlefield, return a permanent you control to its owner's hand.

Wavesifter

Flying
When Wavesifter enters the battlefield, investigate twice. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Evoke {G}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Imprisoned in the Moon

Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Seafaring Werewolf

Seafaring Werewolf can't be blocked.
Whenever Seafaring Werewolf deals combat damage to a player, draw a card.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Suspicious Stowaway

Suspicious Stowaway can't be blocked.
Whenever Suspicious Stowaway deals combat damage to a player, draw a card, then discard a card.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Suspicious Stowaway // Seafaring Werewolf

Elven Chorus

You may look at the top card of your library any time.
You may cast creature spells from the top of your library.
Creatures you control have "{T}: Add one mana of any color."

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

Rejuvenating Springs

Rejuvenating Springs enters the battlefield tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Omen Hawker

{T}: Add {C}{U}. Spend this mana only to activate abilities.

Jolrael, Voice of Zhalfir

At the beginning of combat on your turn, up to one target land you control becomes an X/X green and blue Bird creature with flying and haste until end of turn, where X is the number of cards in your hand. It's still a land.
Whenever a land creature you control deals combat damage to a player, draw a card.

Guardian Project

Whenever a nontoken creature enters the battlefield under your control, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Dryad Arbor

(Dryad Arbor isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G}.")

Briarbridge Tracker

Vigilance
When Briarbridge Tracker enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
As long as you control a token, Briarbridge Tracker gets +2/+0.

Thoughtcast

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Draw two cards.

Hinterland Harbor

Hinterland Harbor enters the battlefield tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Wall of Blossoms

Defender
When Wall of Blossoms enters the battlefield, draw a card.

Fyndhorn Elves

Gala Greeters

Alliance — Whenever another creature enters the battlefield under your control, choose one that hasn't been chosen this turn —
• Put a +1/+1 counter on Gala Greeters.
• Create a tapped Treasure token.
• You gain 2 life.

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Ongoing Investigation

Whenever one or more creatures you control deal combat damage to a player, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
{1}{G}, Exile a creature card from your graveyard: Investigate. You gain 2 life.

Lifecrafter's Bestiary

At the beginning of your upkeep, scry 1.
Whenever you cast a creature spell, you may pay {G}. If you do, draw a card.

Wood Elves

When Wood Elves enters the battlefield, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Ulvenwald Mysteries

Whenever a nontoken creature you control dies, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, create a 1/1 white Human Soldier creature token.

Llanowar Visionary

When Llanowar Visionary enters the battlefield, draw a card.
{T}: Add {G}.

Topiary Stomper

Vigilance
When Topiary Stomper enters the battlefield, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Topiary Stomper can't attack or block unless you control seven or more lands.

Jolrael, Mwonvuli Recluse

Whenever you draw your second card each turn, create a 2/2 green Cat creature token.
{4}{G}{G}: Until end of turn, creatures you control have base power and toughness X/X, where X is the number of cards in your hand.

Harmonize

Inga and Esika

Creatures you control have vigilance and "{T}: Add one mana of any color. Spend this mana only to cast a creature spell."
Whenever you cast a creature spell, if three or more mana from creatures was spent to cast it, draw a card.

Wall of Mulch

Defender (This creature can't attack.)
{G}, Sacrifice a Wall: Draw a card.

Temple of Mystery

Temple of Mystery enters the battlefield tapped.
When Temple of Mystery enters the battlefield, scry 1.
{T}: Add {G} or {U}.

Frilled Mystic

Flash
When Frilled Mystic enters the battlefield, you may counter target spell.

Ice-Fang Coatl

Flash
Flying
When Ice-Fang Coatl enters the battlefield, draw a card.
Ice-Fang Coatl has deathtouch as long as you control at least three other snow permanents.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Collected Company

Look at the top six cards of your library. Put up to two creature cards with mana value 3 or less from among them onto the battlefield. Put the rest on the bottom of your library in any order.

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Mechanized Production

Enchant artifact you control
At the beginning of your upkeep, create a token that's a copy of enchanted artifact. Then if you control eight or more artifacts with the same name as one another, you win the game.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Arcane Signet

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Tireless Tracker

Landfall — Whenever a land enters the battlefield under your control, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on Tireless Tracker.